1 files changed, 96 insertions, 0 deletions

diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 23457b491e8c..2f5b92ef0e53 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -832,6 +832,102 @@ out:
         return ret;
 }
 
+int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int origin)
+{
+        struct inode *inode = file->f_mapping->host;
+        int ret;
+        unsigned int is_last = 0, is_data = 0;
+        u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+        u32 cpos, cend, clen, hole_size;
+        u64 extoff, extlen;
+        struct buffer_head *di_bh = NULL;
+        struct ocfs2_extent_rec rec;
+
+        BUG_ON(origin != SEEK_DATA && origin != SEEK_HOLE);
+
+        ret = ocfs2_inode_lock(inode, &di_bh, 0);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        down_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+        if (*offset >= inode->i_size) {
+                ret = -ENXIO;
+                goto out_unlock;
+        }
+
+        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+                if (origin == SEEK_HOLE)
+                        *offset = inode->i_size;
+                goto out_unlock;
+        }
+
+        clen = 0;
+        cpos = *offset >> cs_bits;
+        cend = ocfs2_clusters_for_bytes(inode->i_sb, inode->i_size);
+
+        while (cpos < cend && !is_last) {
+                ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
+                                                 &rec, &is_last);
+                if (ret) {
+                        mlog_errno(ret);
+                        goto out_unlock;
+                }
+
+                extoff = cpos;
+                extoff <<= cs_bits;
+
+                if (rec.e_blkno == 0ULL) {
+                        clen = hole_size;
+                        is_data = 0;
+                } else {
+                        clen = le16_to_cpu(rec.e_leaf_clusters) -
+                                (cpos - le32_to_cpu(rec.e_cpos));
+                        is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
+                }
+
+                if ((!is_data && origin == SEEK_HOLE) ||
+                    (is_data && origin == SEEK_DATA)) {
+                        if (extoff > *offset)
+                                *offset = extoff;
+                        goto out_unlock;
+                }
+
+                if (!is_last)
+                        cpos += clen;
+        }
+
+        if (origin == SEEK_HOLE) {
+                extoff = cpos;
+                extoff <<= cs_bits;
+                extlen = clen;
+                extlen <<=  cs_bits;
+
+                if ((extoff + extlen) > inode->i_size)
+                        extlen = inode->i_size - extoff;
+                extoff += extlen;
+                if (extoff > *offset)
+                        *offset = extoff;
+                goto out_unlock;
+        }
+
+        ret = -ENXIO;
+
+out_unlock:
+
+        brelse(di_bh);
+
+        up_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+        ocfs2_inode_unlock(inode, 0);
+out:
+        if (ret && ret != -ENXIO)
+                ret = -ENXIO;
+        return ret;
+}
+
 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
                            struct buffer_head *bhs[], int flags,
                            int (*validate)(struct super_block *sb,